Hybrid Color Filter Array Using Local Quality Photoresist
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Solution Overview
Problem
Conventional color filter arrays (CFAs) in semiconductor image sensors require high-grade photoresists for green filters due to human sensitivity, but this increases costs and complexity, while blue and red filters, less sensitive to human vision, often use lower-grade photoresists inefficiently.
Innovation Solution
The method involves using high-grade photoresists for green color filters and low-grade photoresists for blue and red filters, with the ratio of large size pigments in the low-grade photoresists equal to or greater than in the high-grade photoresists, forming a hybrid CFA that improves performance without increasing process costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-grade photoresist is used for all color filters, then manufacturing precision and color accuracy are improved, but manufacturing cost increases
Solution Approach 1:
The patent applies different grades of photoresist to different color filters based on their specific requirements. High-grade photoresist with finer pigment distribution is used for green color filters where color accuracy is critical, while low-grade photoresist is used for red and blue filters where slightly lower precision is acceptable. This local differentiation resolves the contradiction by optimizing manufacturing precision only where needed while reducing overall manufacturing cost.
2Manufacturing precision
If high-grade photoresist is used for green color filters, then color accuracy is improved, but process complexity increases
Solution Approach 1:
The manufacturing process is simplified by dividing the CFA into different regions (green filter regions and red/blue filter regions) and applying different photoresist grades to each. This local quality approach reduces process complexity compared to using high-grade photoresist uniformly across all filters, while still achieving high color accuracy for green filters where it matters most.
3Ease of manufacture
If low-grade photoresist is used for red and blue color filters, then manufacturing cost is reduced, but color accuracy deteriorates
Solution Approach 1:
The patent recognizes that not all color filters require the same level of color accuracy. By applying low-grade photoresist specifically to red and blue filters where human visual sensitivity is lower, the patent reduces manufacturing cost while the resulting color accuracy deterioration is acceptable for these colors. The high-grade photoresist is concentrated on green filters where color accuracy is most critical.
4Manufacturing precision
If uniform high-grade photoresist is used across all filters, then color accuracy is improved, but resource efficiency deteriorates
Solution Approach 1:
The patent optimizes resource efficiency by distributing high-grade photoresist only to green color filters where it provides the most value, rather than uniformly across all filters. This local allocation strategy maintains high color accuracy for green filters while reducing overall consumption of high-grade photoresist material, thereby improving resource efficiency.
Data Source
AI summary
A method for manufacturing a color filter array having hybrid color filters includes providing a high-grade photoresist and a low-grade photoresist, forming a plurality of first color filters on a substrate, and forming a plurality of second color filters and a plurality of third color filters on the substrate. The first color filters include the high-grade photoresist, and the second color filters and the third color filters include the low-grade photoresist. The high-grade photoresist of the first color filters includes a first amount of large size pigments in one unit area and the low-grade photoresists of the second color filters and the third color filters include a second amount of large size pigments in one unit area. A ratio of the second amount to the first amount is equal to or larger than 1.